(Repeats story to add metadata, no change to text) By Liana B. Baker March 21 (Reuters) - Citigroup Inc will go to the Rio Games this year with a sponsorship roster deep in household names like gymnast Gabby Douglas and beach volleyball's Kerri Walsh Jennings, but the U.S. bank is also betting on rugby, a new Olympic sport unfamiliar to many Americans. Citi, which announced its Olympic lineup on Monday, believes its sponsorship of Carlin Isles, an Olympic hopeful little known outside rugby, could bring attention to "rugby sevens," a TV-friendly format of rugby that sponsors said could catch on with American audiences, much like soccer has in recent years. If Isles makes the cut, Citi could get a two-sport athlete for the price of one, said Tina Davis, managing director of marketing and corporate sponsorships at the bank. More...